Climate Feedback

‘Decade break’ in global warming

earth from space nasa glenn.jpgA paper in this week’s Nature predicts that, rather than warming, North Atlantic sea surface temperatures may actually decrease slightly in the next decade. What’s more, the paper suggests global surface temperatures may not actually increase either.

Has global warming stopped? Is this a nail in Al Gore’s coffin?

Well, no.

Despite headlines such as ‘Doubt is cast over global warming’ and ‘Global warming could stop NATURALLY for ten years, say scientists’ that is not what this paper is about.

What this new paper by Noel Keenlyside, of the Leibniz Institute of Marine Sciences in Germany, sets out to do is incorporate data on short term variations in climate into our models of climate change. By doing this they push us into the arena of creating shorter term predictions, in this case of the next decade.

In a “News and Views” commentary on the piece in the same issue of Nature Richard Wood explains:

Keenlyside and colleagues’ model uses a very simple ocean initialization method in which they add heat to or remove it from the ocean surface until sea surface temperatures across the globe are close to observed values. They use their model to produce a set of retrospective ‘forecasts’ starting from earlier states, which they test against what actually happened. Their system produces refined temperature predictions a decade ahead for large parts of Europe and North America.

As Woods points out, colleagues of his at the Hadley Centre in the UK published a similar sort of prediction research of a similar sort, though rather different in approach and with significantly different predictions, in Science last year, as we reported at the time. Combining real world data and modelling this way has only recently become possible.

The new model predicts North Atlantic, European and North American sea surface temperatures will cool slightly; tropical Pacific temperatures will likely be almost unchanged and global temperatures will probably be offset by this variation.

This does not mean we don’t need to worry about global warming. “The natural variations change climate on this timescale and policymakers may either think mitigation is working or that there is no global warming at all,” says Keenlyside (Reuters).

As the NY Times’s Andrew Revkin notes on his blog:

Whether their prediction of a plateau for warming for a decade in North America and Europe is correct or not, their research may signal a shift that many climate researchers have been calling for for awhile now — toward service-oriented climate science …

The NY Times wraps up its main piece with a useful quote from Kevin Trenberth, of the US National Center for Atmospheric Research: “Too many think global warming means monotonic relentless warming everywhere year after year. It does not happen that way.”

Not everyone is happy though. Here’s the always-worth-listening-to Roger Pielke Jr on his Prometheus blog:

I am sure that this is an excellent paper by world class scientists. But when I look at the broader significance of the paper what I see is that there is in fact nothing that can be observed in the climate system that would be inconsistent with climate model predictions. If global cooling over the next few decades is consistent with model predictions, then so too is pretty much anything and everything under the sun.

Image: NASA Glenn Research Center (NASAGRC)

Cross posted by Daniel Cressey on The Great Beyond

Comments

  1. Report this comment

    Gavin said:

    Please revisit your quote about ‘global cooling’ (last paragraph) – Figure 4 in the actual paper shows the global mean temperature trends and there is no projected cooling, merely a slowdown in warming for 10 years and then a rapid increase. Note also that the un-initialised run is closer to the observations in any case.

    This is a classic case where an otherwise interesting paper finds itself reframed based on an onoging ‘global cooling meme’ that has no basis in fact or logic. It’s good to see you pointing this out in the coverage.

    However, Pielke’s ‘big picture’ request is more of a rhetorical trick than a serious question. There are an infinity of observations of the climate system that would raise questions for the models (long term stratospheric warming, evidence for negative correlations over large spatial/temporal scales of water vapour and temperature, long term decreases in ocean heat content etc.). However, he appears to want to restrict observations to short term weather and interannual variability – which are almost orthogonal to the long term trends that climate models agree on. It is, as another commenter on Prometheus said, like trying to disprove the coming of summer by noting that tomorrow might be colder than today. The models have an envelope of internal stochastic variability that is comparable to the observed range, only events and trends that fall outside that range are useful for either the detection or attribution of climate change.

  2. Report this comment

    Steve Bloom said:

    Olive, I honestly don’t know why you thought RP Jr. had anything useful to say on this. See the comments on his post from James Annan and Simon Donner.

  3. Report this comment

    Alec Rawls said:

    This is the alarmist’s attempt to maintain their global warming fantasy in the face of a cooling world. It actually is possible for an oscillation of cold ocean surface water to mask global warming (where an active sun is raising the average temperature of the oceans), and it even happened a mere 60 years ago (between 1940 and 1960), but this is NOT what is happening now.

    Instead, we have a very dangerous situation where the cooling effect of a fall off in solar activity is being compounded by cold Pacific and Atlantic oscillations. Warming effects incur negative feedbacks that make them self limiting. Not so with cooling effects, which regularly plunge the world into 100,000 year long ice ages, with the next one due any century now. We should be guarding against this very real danger by pumping out as much greenhouse gas as we can, tailored to patch the infrared “holes” in our greenhouse blanket. My post here.

  4. Report this comment

    Bishop Hill said:

    Pielke Snr has some interesting comments on Trenberth’s quote about monotonic warming. He points out that the IPCC has forecast exactly that. None of their scenarios, storylines, predictions, call them what you will, said anything about warming stopping for several decades.

  5. Report this comment

    Mick said:

    What about the Sacred Truth enunciated at the Bali Conference?

    I thought it was the Ultimate Consensus of Heavenly Scientific Truth not to be questioned for all Time?

  6. Report this comment

    Patrick M. said:

    “Too many think global warming means monotonic relentless warming everywhere year after year. It does not happen that way.”

    They think this because every wiggle in the temperature chart and every hurricane was laid at the foot of man-made global warming in news reports. Such alarmism is misleading poppycock.

    The IPCC needs to recognize natural variability as a significant factor of our climate today and acknowledge and make clear in reports that not all climate changes and events are due to man, and that a portion of recent warming and potential future trends is natural variability (likely to solar fluctuations). Unless and until they do, the climate scientists and IPCC will lose credibility as predictions get trumped by reality.

  7. Report this comment

    Dr. Gerhard Loebert said:

    THE CENTRAL SUBJECT OF CLIMATOLOGY

    Dr. Gerhard Löbert, Munich. April 24, 2008

    In my opinion the researchers in climatology should put aside their present work for a moment and focus their attention on the central and decisive subject of climatology. This is the extremely close correlation between the changes in the mean surface temperature and the small changes in the rotational velocity of the Earth in the past 150 years (see Fig. 2.2 of http://www.fao.org/DOCREP/005/Y2787E/y2787e03.htm), which has been ignored by the mainstream climatologists. Everything else in climatology follows from this one central theme.

    Note that temperature lags rotation by about 6 years.

    Since temperature is lagging rotation it cannot be influencing the latter. On the other hand, it cannot be envisaged how rotation should influence temperature. Hence, a third agent must be driving the two. The solution is given in http://www.icecap.us/images/uploads/Lobert_on_CO2.pdf . There it is shown that small-amplitude vacuum density waves generated by the motion of the supermassive objects located in the center of the Galaxy are constantly acting on the Sun and the Earth and are thereby producing a series of physical reactions within these celestial bodies.

    Remember: Everything in climatology follows from this one central theme.

  8. Report this comment

    Gavin said:

    With respect to my first comment, on further examination of the paper and discussions with the authors, Keenlyside et al do predict a global cooling from 1994-2004 mean to the 2000-2010 mean. My first statement was based on an incorrect reading of Figure 4 – the green line is not a model trajectory.

    This raises another issue though – which is that since we are almost all the way through the second period already and no decadal mean cooling is evident, the likelihood of this prediction being close to reality is very small. See the latest post at http://www.realclimate.org/index.php/archives/2008/05/global-cooling-wanna-bet/ for more details.

Comments are closed.